Ankylosaurus

Ankylosaurus was a dinosaur that lived 69-65 million years ago. It measures about 27 feet long and had a rigid armor scattered by the head, back and tail (even the lids were stiff). To defend themselves if the armor was not enough, had a stiff ball of 70 kg at the tip of the tail that was able to break the leg of a predator like Tyrannosaurus rex. Its only weak point was the soft belly and it's unarmored legs.

Ankylosaurus is the largest known ankylosaurid dinosaur, estimated to have been up to 6.25 m (20.5 feet) long, 1.5 m (4.9 feet) wide, and 1.7 m (5.6 feet) tall at the hip. This length has been proposed by American palaeontologist Kenneth Carpenter, and is based on the largest known skull (specimen NMC 8880), which is 64.5 cm (25.4 inches) long and 74.5 cm (29.3 inches) wide. The smallest known skull (specimen AMNH 5214) is 55.5 cm (21.9 inches) long and 64.5 cm (25.4 inches) wide, and this specimen is estimated to have been 5.4 m (18 feet) long and around 1.4 m (4.6 feet) tall. Other authors have proposed a body length of 7 m (23 feet), 7.9–9.1 m (26–30 ft), or more than 9.1 m (30 feet). The weight of the animal has been estimated at 6 tonnes (13,000 lb).

The structure of much of the skeleton of Ankylosaurus, including most of the pelvis, tail and feet, is still unknown. It was quadrupedal, and its hind limbs were longer than the forelimbs. The scapula (shoulder blade) and coracoid (a rectangular bone connected to the lower end of the scapula) of specimen AMNH 5895 were fused, and had entheses (connective tissue) for various muscle attachments. The scapula was 61.5 cm (24.2 inches) long. The humerus (upper arm bone) was short and very broad, and about 54 cm (21 inches) long in specimen AMNH 5214. The femur (thigh bone) was very robust, and 67 cm (26 inches) long in AMNH 5214. While the feet of Ankylosaurus are incompletely known, the hindfeet probably had three toes, as is the case in related animals.

The cervical vertebrae of the neck had broad neural spines that increased in height towards the body. The front part of the neural spines had well developed entheses, which was common among adult dinosaurs, and indicates the presence of large ligaments which helped support the massive head. The dorsal vertebrae of the back had centra (or bodies) that were short relative to their width, and their neural spines were short and narrow. The dorsal vertebrae were tightly spaced, which limited the downwards movement of the back. The neural spines had ossified (turned to bone) tendons, which also overlapped some of the vertebrae. The ribs of the last four back vertebrae were fused to them, and the ribcagewas very broad in this part of the body. The ribs had scars that show where muscles attached to them. The caudal vertebrae of the tail had centra that were slightly amphicoelous, meaning they were concave on both sides. The interlocked zygapophyses (articular processes) of the caudal vertebrae formed a V-shape when seen from above.

Like other ornithischians, Ankylosaurus was herbivorous. Its wide muzzle was adapted for non-selective low-browse cropping. The teeth of Ankylosaurus were worn on the face of the crowns, rather than on the tip of the crowns, as in nodosaurid ankylosaurs. In 1982, Carpenter ascribed two very small teeth to baby Ankylosaurus, which originate from the Lance and Hell Creek Formations and measure 3.2 to 3.3 mm in length, respectively. The smaller tooth is heavily worn, leading Carpenter to suggest that ankylosaurids in general or at least the babies did not swallow their food whole but employed some sort of chewing.

A specimen of the related Pinacosaurus preserves large paraglossalia (triangular bones or cartilages located in the tongue) which show signs of muscular stress, and it is thought this was a common feature of ankylosaurs. Some researchers have suggested that ankylosaurs relied heavily on muscular tongues and hyobranchia (tongue bones) when feeding, since their teeth were fairly small and were replaced at a relatively slow rate. Some modern salamanders have similar tongue bones, and use prehensile tongues to pick up food.

In 1969, Austrian paleontologist Georg Haas concluded that despite the large size of ankylosaur skulls, the associated musculature was relatively weak. He also thought jaw movement was limited to up and down movements. Extrapolating from this, Haas suggested that ankylosaurs ate relatively soft non-abrasive vegetation.[22] However, later research on Euoplocephalus indicates that forward and sideways jaw movement was possible in these animals, the skull being able to withstand considerable forces. Though ankylosaurs may not have fed on fibrous and woody plants, they may have had a more varied diet, including tough leaves and pulpy fruits. Based on the broadness of the ribcage, Ankylosaurus may have digested though a hindgut fermentation system like modern herbivorous lizards, which have several chambers in their enlarged colon

The Ankylosaurus appears in the fourth episode (End Game) and it is shown first being a walk way for a Pachycephalosaurus and 2 baby T. rexes. We later see it sleeping in the forest floor. When he awakes it walkes on the beach to eat some berrys. A Pachycephalosaurus is chased by a pair of Troodon and it hides below the Ankylosaurus. Just when a Troodon approaches, the big herbivore sits on it and the Pachycephalosaurus escapes. Just when the Ankylosaurus rises, the Troodon runs away. A young Tyrannosaurus named Junior plays with him, but is driven away by its powerful tail. When the asteroid crashes on Earth, the Ankylosaurus is found dead.